Embolotherapy with platinum microcoils delivered through the Tracker-18 microcatheter (Target Therapeutics, San Jose, Calif) was performed in 16 patients when peripheral superselective catheterization with standard angiographic catheters was not possible. The Tracker-18 catheter could be directed distally into small peripheral vessels for delivery of the microcoils. These microcoils, with attached fiber strands, resulted in vascular occlusion within a few minutes in all cases. Embolotherapy was technically successful in all patients. The procedures were clinically successful in 15 of 16 patients (94%), and no complications were encountered. Embolization with platinum microcoils through the Tracker-18 catheter is useful when standard methods of embolization are not possible.